At least 5 Cornish battalions had unit symbols, a bit like the regular troops divisional shoulder patches, I remember one had a picture of a Cornish Chough. Does anyone else know of any other unit patches that were used.

The Walmington-on-Sea Home Guard had 'CP 1' as their identifier. Perhaps a fictitious designation for 'Cinque Ports'?

At least one of the two Llanelli battalions (Carmarthenshire) wore the 'Scarlet Sospan' badge that was traditionally worn by the 4th (TA) Battalion of the Welch Regt (then with 53rd (Welsh) Division), which was also raised in the town. The badge commemorates the town's tinplate works, the Llanelli 'Scarlets' rugby team and the popular rugby song 'Sospan Fach'.

My grandfather and great-grandfather were in one of the two Haverfordwest battalions (Pembrokeshire).

I expect you might be the chap to ask. I have my Grandfather's Defence Medal, which I guess means he was in the Home Guard in WW2, probably 20th Glamorgan (Port Talbot) Bn. Any tips on finding out if this is right and accessing any records?

I don't know for certain and it's not something I've researched, but it seems that county archives hold most Home Guard records – it certainly seems to be the case in the Pembrokeshire county archive, as I saw boxes and boxes of Home Guard records held there when I was looking for information on the 1790s equivalent. The West Glamorgan Archive (which is the archive for the old county of West Glamorgan, as well as the modern county of Swansea and the county of Neath & Port Talbot) might therefore be your first port of call:

What's curious is that neither my grandfather or my great-grandfather had medals from WW2, despite them being L/Cpl and CSM respectively in the Home Guard. I've got my great-grandfather's medals from WW1 though. Sadly, it wasn't unusual for people to be overlooked when the medals were dished out and it's been my enormous honour to organise medal presentations for a few old gents whose medals finally caught up with them:

Yes, it was collossal and the most surprising thing is that after the initial supply problems, their small-unit firepower was astonishingly good, thanks to Lend-Lease.

An inventory I found for one of the Pembrokeshire Battalions in 1941 showed rifle sections each equipped with 1x Lewis, 2x BAR, 2-3x Thompsons and 5x Sprngfields! Added to this was a platoon of water-coolled Browning .30s at battalion level, plus US-supplied 60mm and 81mm mortars.